- From: Larry Masinter <LMM@acm.org>
- Date: Mon, 21 May 2001 10:27:06 -0700
- To: <www-rdf-logic@w3.org>
I'm hoping that RDF can be modified in a way that distinguishes between the use of RDF to make assertions about actual web resources (data content) and its use to make assertions about things that are described or referenced by things on the net. The use of "http" URIs as unique identifiers for things that are not resources backed by HTTP web servers is a serious confusion of levels. The model for the sentence The students in course 6.001 are Amy, Tim, John, Mary, and Sue. is written in RDF/XML as <rdf:RDF> <rdf:Description about="http://mycollege.edu/courses/6.001"> <s:students> <rdf:Bag> <rdf:li resource="http://mycollege.edu/students/Amy"/> <rdf:li resource="http://mycollege.edu/students/Tim"/> <rdf:li resource="http://mycollege.edu/students/John"/> <rdf:li resource="http://mycollege.edu/students/Mary"/> <rdf:li resource="http://mycollege.edu/students/Sue"/> </rdf:Bag> </s:students> </rdf:Description> </rdf:RDF> This example shows the confusion -- the description is not about the web page at http://mycollege.edu/courses/6.001, but it's about the course which is described by the web page at http://mycollege.edu/courses/6.001. However, we may also want to make assertions about the web page: when it was written, who wrote it, when it was last updated, where it is archived, etc. The web page and the thing the web page is about are at different levels of quoting, but these levels are confounded in RDF today. Adding a "#" at the end of the Description's about attribute's URI doesn't really help, since it resolves into the structural granuarity of the web page rather than into the next level of reference. I can think of several ways of fixing this, but they're all somewhat unpleasant: - leave RDF as is, add another URI scheme that means 'the thing described by this URI' <rdf:description about="ttdb:http://mycollege.edu/courses/6.001"> (ttdb - the thing described by ) - leave RDF as is, assume ttdb, and add a level of quoting if you want to use RDF for metadata, e.g., <rdf:description about="data:text/uri,http://mycollege.edu/courses/6.001"> - Define that each relationship should be specific about its level of indirection, e.g., "dublin core RDF relations are about the URI as a web resource, but other kinds of RDF assertions might really about the thing described by the web resource rather than the web resource itself".
Received on Monday, 21 May 2001 13:30:38 UTC